Webb telescope detects mysterious methane emissions from isolated brown dwarf

Author : Andrew Luc | Published On : 14 Jan 2024

Astronomers using the James Webb Space Telescope have made an unusual discovery: the isolated brown dwarf W1935 shows infrared methane emissions, which may indicate the existence of polar lights such as those at Earth's North Pole, reports OstanniPodii.com.

But there's a problem: since W1935 is devoid of a star, which is usually needed to create the stellar wind responsible for the auroras.

On Earth, auroras are born when solar particles captured by Earth's magnetic field collide with gas molecules in the atmosphere, producing bright light displays near the poles. For gas giants in our solar system, such as Jupiter and Saturn, the auroras are the result of both solar wind interactions and due to active satellites such as Io and Enceladus. The lack of stellar wind around the isolated brown dwarf W1935 leaves the energy source of its upper atmosphere and resulting methane emission unclear.

The research team suggests that the auroras may arise from interactions with interstellar plasma, an undetected active satellite, or from internal atmospheric processes similar to those on Jupiter and Saturn.

The discovery by the team of astronomers, presented at the recently held 243rd meeting of the American Astronomical Society in New Orleans, is significant because W1935 is the first auroral candidate outside the solar system with a methane emission signature and is also the coldest known auroral candidate outside our system.

The sensitive instruments of the JWST Space Telescope have allowed astronomers to detect this unique emission and, with the help of computer modeling, suggest the presence of a temperature inversion in W1935's atmosphere, where the temperature rises with altitude, a phenomenon commonly observed on planets with nearby stars.